Public Petitions Committee

Meeting date: Tuesday, May 26, 2015

Official Report 531KB pdf

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Continued Petition

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American Signal Crayfish (Trapping) (PE1558)

Good morning and welcome to the 11th meeting in 2015 of the Public Petitions Committee. I remind everyone to switch off their mobile phones and other electronic devices, as they interfere with the sound system.

We have received no apologies from members.

Agenda item 1 is consideration of a continued petition, PE1558, by John Thom, on behalf of the RNBCC Crayfish Committee, Ken-Dee catchment, on the American signal crayfish. As previously agreed, the committee will today take evidence from the Scottish Environment Protection Agency and Scottish Natural Heritage. I welcome Dr Scot Mathieson, from SEPA, and Professor Colin Bean, from SNH. I also welcome Alex Fergusson MSP, who has a constituency interest in the petition.

I invite Professor Bean to make a short opening statement, after which we will move to questions.

I thank the committee for inviting Scot Mathieson and me to talk to you today. This will be a joint opening statement on behalf of SNH and SEPA.

Invasive non-native species—or INNS, as I will refer to them from now on—are considered to be the second most important reason for biodiversity loss globally, after habitat loss and fragmentation. They are extremely damaging to our environment, economy and health and cost Scotland as much as £250 million annually.

Crayfish are highly invasive. As you have heard, they have been introduced to a number of bodies of water. Where they have been introduced, they have the potential to have adverse impacts on the aquatic ecology of many of our freshwater habitats.

To put this in context, the Convention on Biological Diversity placed an emphasis on INNS prevention measures, on the basis that that is better than the cure. Once INNS become established, their control or eradication can be technically challenging. It can be very expensive and, in some cases, it is not even possible. Prevention is the least environmentally damaging option. With adequate resources, it can be applied to a greater or lesser extent across the whole spectrum of invasive species threats. That principle is repeated and given the greatest priority in the Convention on Biological Diversity’s Aichi targets, the European Union biodiversity strategy and the 2020 challenge for Scotland’s biodiversity.

EU regulation 1143/2014, on INNS, introduces a statutory requirement on member states to ban the keeping, transportation and sale of species of EU concern. Signal crayfish are a species that is being considered for listing in that regard, with priority being given to species that have yet to arrive and those that are at an early stage of their invasion.

The habitats directive and the water framework directive also require action to prevent the deterioration of vulnerable habitats and species. Scotland is renowned for the quality of its rivers and has international responsibility for its freshwater pearl mussel, lamprey and Atlantic salmon. The spread of signal crayfish has the potential to have adverse impacts on those interests, and that could affect our ability to meet the requirements of those directives.

The top priority with regard to signal crayfish is to prevent their spread to other catchments. The distribution of signal crayfish is quite limited. In 2010, it was estimated that 174km of river length was infested with signal crayfish; that is 0.1 per cent of the river length in Scotland. They are, of course, present in some of our lochs and ponds, Loch Ken being the reason that we are here today. Signal crayfish are, in most instances, unable to move between catchments. They are not great movers in their own right. They tend not to move between catchments without the help of humans and it is vital to prevent a deliberate or accidental movement between catchments.

SNH and Marine Scotland have considered several applications in the past for licences to trap signal crayfish in Loch Ken. SNH as the licensing authority assesses all licence applications objectively. We have to weigh the benefits of trapping against the risk of encouraging further spread. If we allow a commercial crayfish fishery to develop in Scotland, there is a high risk of encouraging the deliberate introduction of crayfish to other catchments. That is supported by evidence from elsewhere, where giving a commercial value to non-native crayfish has resulted in further introductions to previously uninvaded areas in a number of countries. Studies in Sweden and Spain have demonstrated that the establishment of crayfish fisheries has led to their increased dispersal to new areas, often to develop a new fishery in other waters.

The policy position of the Great Britain non-native species programme board, of which the Scottish Government is a member, is that there should be a presumption against the commercial exploitation of invasive non-native species. The only circumstances in which regulatory authorities should permit their commercial exploitation are where INNS are widely established and commercial exploitation is unlikely to jeopardise the potential for future management prospects. In other words, it should not make the situation worse. Any proposal that creates a market incentive for people to introduce signal crayfish elsewhere in Scotland has the potential to make the situation worse.

Trapping is regularly proposed as a solution to the crayfish problem, most often by individuals who wish to exploit populations in Loch Ken or elsewhere in Scotland, either for personal consumption or for sale. It is widely accepted, however, that trapping does not remove all life stages of crayfish and is not effective as a method of eradication. Although high-intensity trapping may reduce the numbers of large crayfish—particularly male crayfish—in some areas, the resulting compensatory growth in production of wild crayfish can mean that the benefits are lost.

Where trapping is licensed in the United Kingdom, both the Environment Agency and the Centre for Environment, Fisheries and Aquaculture Science admit that there are weaknesses in their licensing systems. The blanket ban on keeping live crayfish in Scotland is clearer and more enforceable than the postcode map of go and no-go areas in England, which allows live crayfish to be shipped into no-go areas for the catering trade. That situation led to the tabling in 2013 of cross-party early day motion 659, which called on the Government

“to give urgent consideration to emulating Scottish biosecurity control measures in England and Wales, to review the 2004 Crayfish Byelaws and to ban the live transport and sale of all alien crayfish species in England and Wales.”

Prevention is a top priority in tackling the spread of signal crayfish between river catchments. The check, clean, dry campaign is a GB-wide biosecurity campaign to raise the awareness of water sports enthusiasts about the risks of non-native species introductions. Those three simple hygiene steps have been shown to significantly reduce the risk of spreading invasive plants and animals between catchments on damp equipment.

SEPA has been working with a range of national water sports and fishing groups to promote the check, clean, dry campaign across Scotland. Since 2012, more than 380 fixed signs have been installed at key locations. More than 8,000 leaflets and posters have been distributed and many partners now feature check, clean, dry on their websites and include biosecurity in their training programmes.

SEPA has also just produced a biosecurity pack for event organisers, which is endorsed by a range of water sports users. Both SNH and SEPA recognise the impact that the negative press about crayfish in Loch Ken has had on businesses that rely on visiting anglers. This year, we will begin a survey of angling catches with a view to assessing the future viability of that fishery in Loch Ken. One of the project’s aims will be to promote the opportunities that the area has to offer visiting anglers.

Together with the Forestry Commission, Dumfries and Galloway Council, SNH and SEPA are promoting alternative green tourism activities in the area. Dumfries and Galloway Council has gathered ideas for ways to promote the landscape and the natural heritage of the River Dee catchment and is due to submit a funding bid to the Heritage Lottery Fund this week.

Nature-based tourism is worth £1.4 billion a year to Scotland’s economy and it supports 39,000 full-time equivalent jobs. Field sports, including angling, contribute around a tenth of that total, or £136 million per annum. Local initiatives such as the Galloway kite trail, 7stanes and dark skies are already attracting new visitors to the area.

As a licensing authority, SNH is open to discussing any proposals for the control of signal crayfish in Loch Ken. However, they must address the risks of encouraging their spread elsewhere. The top priority is to manage the threat and prevent the spread of signal crayfish in Scotland.

Thank you for your statement. The Rural Affairs, Climate Change and Environment Committee recently completed some work on biodiversity. Following that work, the committee sent a letter to the Minister for Environment, Climate Change and Land Reform, in which it said:

“we are aware that not only are American signal crayfish highly destructive to local ecosystems but their invasive nature means this may become a national issue if effective and urgent steps are not taken.”

Do you agree with the RACCE Committee on that?

There are two ways of answering that, the first of which is to put the situation into context. In our opening statement, I mentioned that 174km of waterways are infested by signal crayfish. That is equivalent to 0.1 per cent of all the waterways in Scotland. The problem in Scotland is very small when we compare it with that in other parts of the UK. I have some other contextual data. In England, 11,246km out of 46,939km of waterways are infested. That is a real problem.

Secondly, the real issue in Scotland is the prevention of the further spread of these animals. Signal crayfish have relatively poor powers of dispersal, although you might have heard that they can get out of the water and walk for miles to infest new catchments, rivers and lochs. That is simply not true. They can move out of water and live on land for a short period of time, but they cannot move far. They have very limited powers of dispersal.

The animals appear where they do, which is as far south as Loch Ken and as far north as the River Nairn, because people have moved them there. Signal crayfish have no clear natural invasion pathway. The key issue is the prevention of the introduction of new populations.

Once signal crayfish have been introduced into a body of water, it is almost impossible to remove them. In very small water bodies, such as ponds, we have been able to eradicate them by using biocides. Scotland is a leader in the UK and Europe when it comes to the number of attempts we have made to eradicate crayfish from our waters. Once they have been introduced into rivers or large lochs, such as Loch Ken, the prospect of eradication is nil. The clear driver is to prevent the animals from being introduced in the first place. Although they are incredibly damaging where they occur, the real trick is to ensure that they do not get there in the first place. The real problem, then, is how we manage people rather than managing the animal.

You gave the statistic that 174km of waterways in Scotland are infested by these invasive fish. How long has it taken to get to that point?

10:15  

Crayfish were first recorded in Scotland in 1995. Ironically, that was in the Dee system, in Kirkcudbrightshire, where Loch Ken is situated. They had undoubtedly been there for some time before that. By the time that people notice that crayfish are present, they will already have been there for some time and will be established. At a conservative estimate, I would say that they have probably been in the Dee-Ken system since the 1980s. However, in 2015 there are crayfish in 174km, or 0.1 per cent, of our waterways, so we are not talking about an animal that will spread at a rate of knots throughout Scotland. Many parts of Scotland are not particularly suitable for crayfish anyway, but that gives you an idea of how quickly the animals spread and a bit of context about how fast they have been moving.

We generally pick up on a new population every year, usually in a place that is far removed from the next possible source of infestation. For example, we found out last week that a signal crayfish population had been introduced to a small pond in the middle of Coatbridge, the Tarry pond. Such findings occasionally come up. There is no population of crayfish near there and they could not have moved there under their own steam. That population probably came from somewhere on the Clyde. The upper Clyde, like the Dee system, is infested with the animals too.

I want to pick up on a point that was made about the situation in England. It seems that there is a worse problem in England, but I am curious as to whether any attempt has been made down there to commercially trap American signal crayfish.

There is a well-established commercial fishery for crayfish in England. In fact, that is where the Scottish populations will have come from. Crayfish were introduced into England and Wales in the late 1970s and early 1980s and their introduction was encouraged by the Ministry of Agriculture, Fisheries and Food at the time as part of a diversification programme. Unfortunately, crayfish are the Steve McQueen of the invertebrate world and they promptly escaped. They are pretty good at burrowing out of things so, of course, new feral populations were established in the wild.

There is a well-established crayfish industry in England, which is managed by different means. As I mentioned, there are go and no-go areas there. There is a postcode system—the areas were set in 1996 and have not moved since then—and people are allowed to exploit crayfish for personal consumption in certain postcode areas. However, there are several gaps in the legislation. Colleagues from the Centre for Environment, Fisheries and Aquaculture Science have said that the Import of Live Fish (England and Wales) Act 1980—the legislation that is used to control crayfish exploitation in England—has slowed down the spread but has not stopped it.

There is clearly an incentive for people who exploit that resource to maintain and increase their fishing opportunities. If you look at the websites for many crayfish companies, you will see that they actively look for new water bodies to exploit. Those are the same people who wish to exploit Loch Ken.

Can the witnesses update the committee on the actions that have been taken as a result of the meeting that was held by Paul Wheelhouse in July last year? Specifically, what is being done to restore confidence in Loch Ken as a coarse fishing destination?

Thank you for the opportunity to address the committee. Several key points came out of the minister’s meeting on 31 July.

There was a proposal to take forward further work on the fishery in Loch Ken and its status, a proposal to do further work on the population in Dalbeattie with a view to introducing measures to control or address the problem there, and a suggestion on the promotion of biosecurity. There was a further suggestion that the minister would take away the need to do further work to promote tourism and other activities in the area. I can cover progress on the first three matters, but I have not been involved with the minister’s commitment to tourism.

The survey to assess the status of freshwater fish was really intended to assess the viability of the loch as a fishery and was an opportunity to see whether the suggestions that the fishery was no longer viable were supported by evidence. We now have in place a project proposal for a survey of coarse fish that will use the angler surveys and a potential fishing event. That will allow us to gather data and promote angling and biosecurity to the community there. Funding for that project has been secured from SEPA and SNH, and the work will take place over the summer.

On the back of the minister’s meeting, a Heritage Lottery Fund bid has been developed, which is being led by Dumfries and Galloway Council. I believe that the bid is to be submitted at the end of this week. Funding for that project would start in 2017, and the fishery survey is interim preparatory work towards that. It was proposed that, if the bid was successful, it would help to fund the setting up of a group to promote angling in Loch Ken and the catchment, to review the existing Loch Ken management plan and to produce a fishery management plan that would be informed by the citizen data that we hope to start to collect this year.

SEPA and Scottish Water have been working closely to assess the feasibility of options and to produce an action plan for Dalbeattie reservoir, which should be completed within the next month, with a view to putting in place initial measures in the summer of 2015. From speaking to local colleagues, we know that there is discussion of the potential for eradication. The potential exists to isolate the reservoir and treat the population to remove it—as Colin Bean has outlined, that is a feasible option in smaller water bodies. There is the potential for installing what was described to me as a chain mail mesh net across the reservoir with a view to preventing escapes into the river, and that option is being considered.

The Galloway Fisheries Trust has continued surveying in the area around Dalbeattie reservoir to inform the decision process. The most recent survey that it undertook was in the late autumn of 2014, and it did not find any evidence of crayfish in the burn downstream of the reservoir, so it looks as though they are still contained in the reservoir, and there is the potential to do something to treat that.

The check, clean, dry campaign, which Colin Bean has outlined, is the key GB approach to the promotion of biosecurity, and SEPA and SNH have been working with a range of national water sports and fishing groups to promote that biosecurity campaign across Scotland. As, I think, Colin Bean said, since November 2012 we have arranged for 380 signs to be placed at key locations such as boat entry points, and 8,000 leaflets and posters have been distributed. The partners that have been involved include the Rivers and Fisheries Trusts of Scotland, the Scottish Federation for Coarse Angling, the Scottish Anglers National Association, the Scottish Canoe Association, the Royal Yachting Association—with the green blue programme—and Triathlon Scotland.

In the Dumfries and Galloway area, we have worked with a number of those partners and the three fishery trusts—the Nith Catchment Fishery Trust, the River Annan Trust and the Galloway Fisheries Trust—to produce a biosecurity information pack for event organisers. That is ready to launch, and we hope to launch it at an event on Loch Ken to promote the guidance in the area.

There is a lot of additional local work on INNS, and specifically on crayfish. I have a long list of that and would be happy to provide the details in a written response, if that would be helpful.

That would be helpful, Dr Mathieson.

The check, clean, dry campaign is promoted by both your organisations. However, the petitioner claims that it is not working or that it

“will not work in its present form”

because

“canoes boats and other small watercraft in the Ken Dee Catchment have no facilities to carry out such a task at the end of the day no one is there to enforce it and a 16 inch by 20 inch sign every 8 miles is not going to inform the public.”

What impact has the campaign had to date, especially given the petitioner’s view that it will not work in its current form?

I am not aware that any monitoring for effectiveness has been put in place yet. However, we are at an early stage in launching the campaign locally, and an effective promotion campaign requires monitoring. If it would be helpful, I could work with local colleagues to identify what they propose to do to monitor effectiveness. I can certainly attest to the efforts that they have been putting in to spread the message locally, which have been targeted both at user groups and more generally to promote awareness in the local community.

It would be good if you could feed back any information.

I will certainly do that.

Thank you.

I have a number of questions on the check, clean, dry campaign. Is there any evidence that the spread in Scotland is anything other than accidental?

The spread of crayfish?

Yes.

Yes. One fishery in the eastern part of the country, not too far away from here, introduced crayfish as a management tool to deal with mortalities, or “morts”. Crayfish can help to prevent disease in a fishery, as dead fish fall to the bottom of the pond and the crayfish remove them. That is one example of deliberate introduction.

Another example of deliberate introduction involved a garden pond in the Tay system. In that situation, we would try to remove crayfish with biocide. There was another deliberate introduction, for consumption, in a series of ponds in the North Esk catchment. The case went to court but was thrown out on a technicality.

There was a deliberate introduction in the quarry pond in Ballachulish, and one can only assume that the introduction of crayfish to the Tarry pond in Coatbridge, which I described earlier, was also deliberate.

I think that those introductions were all deliberate and not accidental at all.

What happens when introductions are found to be deliberate?

It is very difficult. You can imagine how difficult it is to apprehend someone who is carrying crayfish around. You have to be there at the time—the person needs only a couple of crayfish and a bucket, and they can throw them in. Unless the police are there at the point of introduction, there is very little that they can do about it.

As you can imagine, in many water systems, once these things are in, they are in. The chances of removing them are slim to non-existent on most occasions, unless you can manipulate the pond in some way by draining it and removing the individual animals.

Once crayfish have been introduced, they may take many years to become established and, unfortunately, you may not come across them until the population is established. A lot of the records come from anglers, who see them on the bank or in shallow waters.

The potential for accidental introductions is relatively slim. On balance, I think that these things have been introduced deliberately.

On a scale of 1 to 10, which method—accidental or deliberate introduction—do you consider would cause the greatest degree of infestation?

I would say that 9.9 out of 10 cases would involve deliberate introduction and the other 0.1 would involve accidental introduction.

What are you doing to prevent deliberate introduction from happening?

The key is awareness. We have run several workshops and training events for staff from RAFTS, SEPA, SNH and the police to highlight the dangers of introducing these things.

There is a lot of signage and leafleting about signal crayfish. At the end of the day, the key is to promote awareness to prevent these things from being deliberately introduced. We are trying to educate people about the dangers of transporting the animals and about the fact that, once they have been introduced, they will in all likelihood be there in the long term.

10:30  

Would deliberate introduction be responsible in the same number of cases in England or abroad—would it account for about 9.9 out of 10 cases?

I cannot speak for what happens south of the border, as the situation is very different there.

I ask that because, surely, if the introductions there are more accidental than deliberate, they must be doing something to prevent deliberate introductions. Could you find out more about that and get back to the committee?

I will certainly take that away with me.

I will add a little detail to Colin Bean’s response about awareness raising and so on. Dumfries and Galloway is ahead of other parts of Scotland in having a regional invasive non-native species working group, which has been working since 2010. Other parts of Scotland might want to follow that model in due course, as we start to think about how to tackle the range of invasive non-native species. Some of the work specifically on signal crayfish has focused on targeting information that people need to know about the legal status of crayfish and fishing.

After the minister’s meeting at the CatStrand in Dumfries and Galloway in July last year, a “frequently asked questions” leaflet was produced by SEPA and SNH to clarify the legal situation. That leaflet was sent to all the people who attended the meeting at the CatStrand and was then distributed widely through community newsletters in the Loch Ken area and so on. On top of that, SEPA has been working with Police Scotland to translate the signal crayfish posters into a number of languages, because people with a cultural interest in eating signal crayfish may come here from eastern European countries, for example. We are trying to create something that is useful for those sections of the population who are traditionally more interested in crayfish, and in languages that they can understand more clearly.

What evidence from Scotland or anywhere around the world suggests that issuing licences for trapping would incentivise people to move crayfish into new areas?

There is evidence from Sweden and Spain, where the establishment of new licensed fisheries led to the establishment of new unlicensed populations.

Was that related to people deliberately moving in for commercial gain?

Absolutely. There would be no incentive to move signal crayfish from existing fisheries to other water bodies unless someone planned to exploit them.

What about the suggestion that SEPA and SNH could support trapping on a not-for-profit basis if operators worked closely with the organisations—perhaps if the market incentive was taken out of trapping?

That would be similar to the situation in England, where there is a licensed fishery, yet crayfish are still found in new areas. The English situation suggests that, even when areas are tightly controlled, new populations continue to appear.

Let us suppose that a licensed fishery were to be established at Loch Ken. Other populations relatively close to that also contain signal crayfish, so would there be calls to establish a fishery in those as well? The upper Clyde has a particularly bad problem with signal crayfish. It is in the central belt and within touching distance of two of the biggest conurbations in the country. I feel that such an approach would be incredibly difficult to control.

If you believe that licensing is not the answer, what will you do to help eradicate the problem?

That is the key point—once the crayfish are in, we cannot eradiate them. Our first objective must be to prevent the animals from being moved elsewhere. By creating a market for them, we would create the conditions that exacerbated or accelerated the spread of the animals to new areas.

I mentioned the biocide eradication treatment that we have, largely, pioneered in Scotland. We have looked at a range of techniques for the eradication or control of crayfish. We thought that eradication might be a possibility when they first arrived. We were younger and naive then—we thought that techniques such as hand removal, electrofishing and trapping might offer the prospect of eradication, but they clearly do not.

That is not to say that eradication is an impossibility through further developments. We are working with people in other parts of the UK on strategies that we could expand into Scotland. Examples are the use of poisoned baits and the targeting and removal of animals in life stages when they might be more vulnerable, such as when they are moulting or carrying eggs and young.

We are always on the lookout for new techniques—indeed, we are at the forefront of doing so. A number of PhD programmes are looking at the crayfish issue. We are looking at new ways to identify rapidly where the animals can be found. We are using state-of-the-art techniques, such as environmental DNA, to forewarn us of where the animals are, so that we can move in and take action as quickly as we possibly can—even when they are not visible to river users, anglers or whoever—and target the populations before they become fully established.

It would be a mistake to think that we are doing nothing in Scotland, which was a view that one submission to the committee expressed. A lot of work is going on in Scotland, in our sister agencies in England and in Europe. There is no slacking in our endeavours to deal with the issue. We are not putting up our hands and saying that we will forget about it and let everything slide.

Good morning. There seem to be two aspects to the discussion. One is a quite interesting discussion about the containment of signal crayfish; the other is about the petition. We have had an extended discussion about the first part, and little discussion about the second part.

I did not know anything about the issue before the petitioner brought the matter to us. That is typical in the committee—all manner of subjects come to us, and we have to do our best to read through all the paperwork. However, I am bound to conclude that there has been an awful lot of prevarication and that our strategy appears to rely on signage, leaflets and posters, with lots of talk about everything else that is happening, including the work, the discussions and the like.

I am interested to know your prognosis for the strategy that we are employing. Do you expect that, 10 years from now, American signal crayfish will have colonised more waterways in Scotland?

The likelihood is that they will have done so. The cause of that will be human movement.

You said that the licensing schemes in Sweden and Spain have led to the introduction of the crayfish into other waterways. Were licences granted for the additional waterways into which the crayfish population was unofficially extended?

I do not have that information in front of me, unfortunately.

You do not know whether the granting of licences led to an expansion of the population, which led to further licences to allow the crayfish to be commercially exploited.

I know that the granting of licences led to the expansion of new populations, which created an issue.

I am sorry, but I say with respect that you do not know that. You said that, without a licensing regime in this country, you would expect the population to extend as a consequence of casual introduction.

In Sweden and Spain, where there are commercial licences, the populations have expanded. You attest that that is because licences were granted. However, you cannot tell me that licences were subsequently granted for the commercial exploitation of those additional populations; if they were not, there would have been no commercial advantage to the expansion. That is correct, is it not?

On the basis of the information that I have in front of me, yes.

Thank you.

I return to the petition, because I thought that you skated quickly over what Mr MacAskill asked about. The petitioner asks why a licence for the trapping and sale of crayfish on a not-for-profit basis from Loch Ken, which is now deeply infested, is unsupportable when there would be no commercial exploitation and all the proceeds that were raised would be used for future scientific research and teaching, for examining the very problems that you are trying to contain and for the local community’s benefit. That could be done on a not-for-profit basis with no exploitation for commercial gain.

I understand that we do not want crayfish to spread but, given that you cannot attest that there is any evidence in Sweden and Spain that there was commercial gain as a result of licences being granted, where is the evidence that says that a not-for-profit scheme is not an alternative that is worth considering?

We did not say that we would not consider it.

You did. You said to Mr MacAskill, who asked the question, that you have ruled it out.

No. We have had a number of licence applications for Loch Ken. For the most recent licence application, which was in March 2013, we said what we have continually said, which is that we would be happy to look at any application that was scientifically based and could provide good evidence and monitoring that showed that the crayfish population could be controlled. That is what we have said.

That is not what the petitioner is saying; he says that the proposal could fund scientific research, which seems to be rather meagre.

I do not accept that the scientific research is meagre.

How much is being spent?

I think that it is all very—

I am asking a question: how much is currently being spent?

I do not have that figure to hand.

How can you tell me then that it is not meagre?

Because I know the projects that are on-going and I know the—

Perhaps you could itemise them for the committee and let us know how much is currently being spent.

Rightly or wrongly, there seems to be a collective received wisdom in this case—I sometimes come across the same thing elsewhere—that has a momentum all of its own. I wholly support not wanting the crayfish populations to expand, but I am not entirely clear why in a place such as Loch Ken, which is infested with crayfish, the not-for-profit solution that might fund additional research and harvest the crayfish population would inevitably lead to licensing elsewhere. However, even if it did so in the Clyde, what would be wrong with a not-for-profit harvesting operation in the Clyde that also raised funds that were exclusively deployed on future scientific research and teaching? I see a distinction between that and the commercial exploitation for profit that seems to be an incentive, although not one that we can demonstrate has operated internationally.

I go back to the situation in our country—we can look at England and Wales, where crayfish trapping has been licensed.

On what basis is it licensed?

In terms of the exploitation of crayfish for personal consumption, for sale—

But not for not-for-profit purposes.

No—for sale. Crayfish from England and Wales is sold and exported to the continent.

That is my point—that is commercial exploitation.

Absolutely.

I am drawing a distinction between that and not-for-profit exploitation, where no profit could be generated.

Who would carry out the not-for-profit work? The petition mentions 50 trappers and 130 full-time-equivalent jobs or whatever, but no business case is associated with that—frankly, it is just a finger in the air. What would the income—

Surely it is a finger in the air in desperation, because absolutely nothing of any consequence has been attempted that has been successful.

In Loch Ken?

In Loch Ken.

That is because the chances of eradicating crayfish in Loch Ken are zero—absolutely zero.

Until there was experimental trapping, there was not even any understanding of the population itself. Is that correct?

That is absolutely true, but we knew that there was a substantial population.

How do we know that trapping has had no effect on the overall population?

We know from work elsewhere that trapping does not—

How do we know?

10:45  

There is evidence from elsewhere that trapping does not result in the eradication of the populations.

Mr Ribbens of the Galloway Fisheries Trust said:

“The initial five month research has indicated that a heavy trapping programme may be able to have a significant impact on the present crayfish population.”

It can have an impact without eradication.

I did not say eradication.

As the catchable stock is removed, that leaves things such as predation pressure and competition pressure and we get what is called compensatory growth. That means that the population is not reduced; there is the same biomass of animals, but more of them.

That just sounds like a theory, not a fact.

It is not a theory; it has been demonstrated for other species such as pike in pike eradication programmes.

Would part of the licence regime not be that whoever the trapper was would have to catch X, Y or Z per year, so the numbers would diminish? Is that not a form of managing crayfish?

That goes back to my earlier point about monitoring. How would the fishery be managed? Remember that it is a fishery in perpetuity. A massive dent would probably be made in the numbers of catchable-size—largely adult—animals, but we would be left with a population of smaller animals, which grow much faster and will still be reproducing. We would end up with a reduction in the catchable component but the same problem and the same damage, which, it has been said, has denuded Loch Ken of all its biodiversity, although that statement has never been substantiated.

We do not know what the impact on fisheries would be, which is one reason why we are about to kick off the fisheries project. The websites of many of the hotels around Loch Ken contain plenty of photographs of people with large bags of fish. Fish are not missing from Loch Ken.

Undoubtedly crayfish will have had an impact, but the scale of that impact is not clear. We will probably never know, because crayfish have been in there for so long. What baseline might be used? To say that throwing a bunch of crayfish traps in would solve the problem is frankly not true.

It seems to me that you say that it is very unlikely that we will ever eradicate crayfish and, at the same time, you do not want to put in place anything to manage crayfish.

To follow on from Jackson Carlaw, I will ask about licensing. There seems to be a confusion between commercial licensing of crayfish fisheries and the fact that no one can catch or lift a signal crayfish out of the water without fear of prosecution if they get caught. I understand that the petition asks for a licence to be granted to allow people to remove signal crayfish from the water and trap them not on a commercial basis but on the basis of hindering population growth of signal crayfish. What would be the problem with issuing a licence for the trapping of crayfish to allow people to try to eradicate them from a watercourse?

Quite a lot of illegal crayfish fishing goes on in Scotland, including some in Loch Ken. We have never closed the door to trapping to alleviate pressures on, for example, areas of Loch Ken during a fishing event, which we have discussed with Jamie Ribbens.

Any proposal to trap on a large scale in Loch Ken has to form part of a rational management programme. That is not an unreasonable stance to take. We would not support some gung-ho invitation to crayfish trappers around the UK and elsewhere to come and exploit the situation in an unmanaged way—in a way that could end up causing more damage to Scotland plc by creating a market that might accelerate the spread to new areas.

I do not think that the petitioner is looking to get trappers from elsewhere in the UK to come to that stretch of water. They are trying to protect the water and get a licence to trap the signal crayfish that are there.

You referred to a rational management programme. Can SEPA and SNH sit down with the individuals concerned—you claim that you have done that—to work out a rational management programme and help to limit the spread and growth of the signal crayfish population?

You will not have seen this, but I have with me a letter from us to Mr Thom, which we sent following a meeting with him on 4 March 2013. We said:

“We discussed other licensing options and SNH intimated that it would be able to license a non-commercial project with a clear management aim and which is supported by a clear scientific methodology. Such applications would also require a sound monitoring and evaluation element, as well as being fully biosecure. A less robust proposal runs considerable risk of expending considerable time and resource with little or no benefit to any party. Unfortunately we know from bitter experience and considerable cost that intensive trapping of crayfish simply does not work as a means of crayfish control.”

Towards the end of the letter, we said:

“I hope that you find the information above useful. We would be happy to reconsider any application supported by a robust plan that takes into account the issues raised in this letter. As we discussed at our meeting, once you have developed a plan and have the personnel (and any funding required) in place we would be happy to discuss this further with you.”

It does not sound from that as if we have been unreasonable to Mr Thom.

Jackson Carlaw tried to press you on how much money was being spent on academic research in this area. Would it not be possible to work with the local individuals who want to eradicate signal crayfish, and bring in that academic support? You disputed Mr Carlaw’s assertion that very little money was being spent on academic research. Would there be an issue with SNH and SEPA providing support to allow the local community to carry out the monitoring programme in conjunction with you and with the academics who you claim are currently involved in monitoring signal crayfish in Scotland?

The PhDs to whom I referred are all working on separate and particular issues of crayfish biology. Some of them have worked on Loch Ken in the past—Zara Gladman, for example, as the minister knows.

As for directing research moneys towards Loch Ken specifically or crayfish in general, SNH included signal crayfish as a species in the species action framework, which ran from 2007 to 2012. We put a lot of resource into the management and science of signal crayfish.

On the question of providing support for the science element of any management proposal for Loch Ken, I would say that we would of course be able to provide the scientific support or advice required.

It sounds hopeful that you will be able to work with the local community to provide scientific support to allow such a programme to be carried out.

I want to widen out the discussion, because there is another issue that I am rather concerned about. You mentioned the fact that 174km of waterways are infested with signal crayfish, which you said was 0.1 per cent of the waterways in Scotland. You compared that with the situation in England and Wales.

You went on to talk about the Tarry pond in Coatbridge, where you said that signal crayfish were deliberately introduced. What enforcement powers do SNH and SEPA have in relation to people who are found to be breaching the invasive non-native species legislation?

That is clearly set out in the Wildlife and Countryside Act 1981, which was strengthened by the Wildlife and Natural Environment (Scotland) Act 2011. I cannot remember what the monetary or custodial penalties are, but it is illegal to introduce any animal in any place outwith its natural range. I do not think that anyone would argue that signal crayfish, which originated in North America, are within their natural range in Scotland, the UK or Europe.

You mentioned that the police caught the people who introduced signal crayfish in the Tarry pond. Is it the police who carry out the enforcement action, or is it SNH or SEPA?

It is the police.

So the police would need to catch someone who was attempting to introduce signal crayfish, or someone who was trapping them.

Absolutely.

Could you remind us how the incident involving signal crayfish at the Tarry pond was brought to your attention?

It was brought to my attention by the local fisheries trust.

The local fisheries trust monitors a number of ponds and waterways in the North Lanarkshire area.

The Clyde River Foundation, which is the fisheries trust that I am talking about, is putting together a strategic plan for invasive non-native species removal for SNH. As part of that work, it has been looking at records that are held by local rangers and local councils. When it came to our attention that it was possible that signal crayfish might have been introduced in the Tarry pond, the foundation investigated and found signal crayfish there.

I assume that a member of the public went to the foundation and informed it that they suspected that there were signal crayfish in the pond.

I suspect that a member of the public probably went to the local countryside ranger and that the matter was brought to the foundation’s attention through the ranger.

My concern is that incidents such as the one at the Tarry pond could be replicated 100 times throughout Scotland, with individual trusts’ attention only being drawn to them by members of the public.

You say that 174km of waterways are contaminated, and we know that Loch Ken is contaminated. However, we do not know what the full scale of contamination by signal crayfish in Scotland might be. Therefore, what you have told us about the areas that are infested with signal crayfish might just be the tip of the iceberg.

You said that you knew that the upper Clyde was heavily infested with signal crayfish. The upper Clyde flows into the Clyde and runs through the Clyde valley. How do we curtail the spread of signal crayfish along the Clyde and, potentially, every watercourse that feeds off or flows into the Clyde?

I think that you are right—there are probably more populations than we know about.

As far as the Clyde is concerned, there is no prospect of removing crayfish from the Clyde; in fact, there seems to be no real prospect of halting their spread. That is an extremely difficult thing to do, particularly when animals move downstream rather than upstream.

11:00  

We installed a crayfish barrier—the first of its type—at the head of the Clyde at Clydes Burn, precisely to prevent signal crayfish from moving from the head of the Clyde into the river Annan system. Having said that crayfish have poor powers of dispersal, I point out that the logic behind that approach was that the upper reaches of the Clyde and the Annan are connected via a system of field drains. It is not as if the crayfish have to walk across land.

However, the sad fact is that these animals will move downstream. They have done so since they were first found in the area in the late 1990s. Treating smaller ponds with biocide to eradicate crayfish is certainly a possibility, but the idea of using biocide in a river, particularly one the size of the Clyde, is simply a non-starter.

The other issue for me is the protection of our indigenous species in the waterways. I know that salmon have been coming back up the Clyde, but I imagine that signal crayfish predation in the upper Clyde could cause those fish to be eradicated and therefore bring an end to the salmon population in the Clyde.

There are a number of other protected species. For example, you have mentioned Coatbridge, and I note that, according to Scottish Wildlife Trust, the third largest population of great crested newts sits just outside the town. If signal crayfish were to get into those watercourses and ponds, it could lead to the great crested newt being eradicated in that area. What are SNH and SEPA doing to protect those species if, as you have suggested, very little can be done to eradicate signal crayfish?

It is very difficult to identify specific actions to protect those areas other than to prevent the introduction of signal crayfish. I have to say that I am not an expert on great crested newts, but I would imagine that if crayfish got into the systems in the areas that you have highlighted, such as Gartcosh, the impact on the newts would be devastating. The SWT and others monitor those areas very regularly, and I would hope that, if crayfish were to enter those systems, we would have quite a start on them and would be able to act very quickly.

I have no further questions, convener.

I call Alex Fergusson.

As I am very aware of the time, convener, I will be as brief as I can be. I have a considerable local vested interest in the petition, because I live about 200 yards from the top of Loch Ken and this has been a growing issue ever since I moved to that part of the world in 1998.

Perhaps I can put a bit of local perspective on the issue. In his introduction, Professor Bean rightly said that Scotland is renowned for the quality of its rivers. I absolutely accept that, but for many years Loch Ken was also renowned for the quality of its coarse fishing. I have to say that I laugh a little bit when I hear about initiatives to promote the opportunities for angling at Loch Ken, because for many years Loch Ken promoted itself. You have only to look at the guest books and reservation records of the hotels that have been mentioned to see that fishermen have voted with their feet and no longer come to Loch Ken in anything like the numbers that they did. That is not because the fish are not there to catch, but because whenever their bait gets within a few inches off the bottom of the loch, where it needs to be to catch the fish, it gets taken by the signal crayfish. The crayfish are so numerous that you can barely coarse fish in Loch Ken; as I have said, the hotels’ reservation records will back that up. What has happened is that a huge hole has been created in the local economy by the almost uncontrollable spread of this invasive species.

Despite everything that we have heard about on-going work to look at it, the problem, from the local perspective, is frankly one of complacency. Yes, there are leaflets and notice boards extolling the virtues of people cleaning their equipment before they leave the area, even if they have been doing something other than fishing. That has been going on for some years. However, despite what we have heard—I am not really questioning any of what we have heard—the fact is that the spread continues, as has been admitted.

I think that all the measures that we have heard about and which are being taken—including the erection of the barrier at the head of the Clyde, which cost, at around £50,000, a significant amount of preventative money—are simply delaying the inevitable. I believe that that has been admitted.

It was said earlier crayfish are not good movers. There are a lot of people who would dispute that and who believe that they can move up to 2 miles by night.

I am aware of the time. I know that the committee’s consideration of the issue will be on-going. It would be helpful if, when the witnesses write back to the committee, they could identify the number of times a biocidal solution has been used. Of course, I appreciate that there is a scale issue, and that in a body of water the size of Loch Ken that approach will almost certainly not be effective.

I have one further question, by way of wrapping up my contribution. When does an invasive species become an indigenous species? It seems to me that an invasive species is one that ought to be capable of being eradicated, and that, if it cannot be eradicated, we should then consider it to be an indigenous species. Once we consider something to be an indigenous species, we can look at it in a different way.

The solution to the problem has to involve trapping, although not necessarily in a commercial way. It has been admitted that we cannot eradicate the crayfish, but we can surely manage them in a way that we are not doing at the moment. I think that that has to involve trapping and, as I said, if we accept that the species is no longer invasive but has become indigenous, I also think that we can approach the issue in a different way.

Much has been made of the fact that the problem in Scotland is very small compared with that in the rest of the UK. That suggests to me that we could have a much greater focus on it and should be better able to come up with a solution to it, because the issue is much easier to identify in the various locations where it arises. It also seems to me that, if research is going on into the issue, it would be hugely logical to bring it together in a place such as Loch Ken, which is where the largest population of crayfish is. If we did that, at least local people could see that the complacency that I referred to earlier is not the reality.

SEPA and SNH are publicly funded. Where on your priority list does the removal of this indigenous species lie?

The priorities of SNH are set by the Government in our grant-in-aid letter.

Invasive species, including non-native species, are a major cause of biodiversity loss. There are plenty of examples of situations in which radical action is taken in relation to not only species that are not native to Scotland or the UK but species that are native to Scotland but which have been introduced to parts of Scotland where they are not native, as was the case with hedgehogs in the Western Isles. A tremendous amount of resource has been expended on the issue of invasive species. You ask where the issue falls on our list of priorities. I would say that, frankly, everything is a priority these days. However, I would also say that we spend a significant amount of resource in this area.

I should have said “invasive” rather than “indigenous” when I asked my question. I apologise for that.

I ask the committee to decide what action to take on the petition. Members have before them a note by the clerks suggesting a possible course of action.

I would very much like to reflect on everything that I have heard today and on the one or two bits of further information that we will get as a result of today’s discussion; then, at a subsequent meeting, we can discuss the action that we should recommend.

Do members agree with that suggestion?

Members indicated agreement.

I thank Dr Mathieson and Professor Bean for their evidence.

I suspend the meeting for a couple of minutes.

11:10 Meeting suspended.  

11:11 On resuming—